The present invention relates to a heating plate of ceramic, and more particularly, to a ceramic heating plate for being built in a panel heater, the heating plate generating far-infrared rays at an elevated temperature.
As is generally known, there is a ceramic known in the art as generating far-infrared rays when it becomes heated. Such ceramics are recently used as a source of energy for a variety of purposes.
A well-known application is a concealed heating system in which a number of heating plates are built in floors and walls of a building. An advantage of the ceramic heating plates is that they warm the rooms by radiation of heat. Radiation heats objects rather than air so that heat loss due to convection (which causes a higher temperature near the ceiling then at the floor) is greatly reduced. Also radiation phenomena is a lesser user of energy than convection phenomena for transference of heat. The far-infrared rays has a good permeability of heat through a human body, and even if the entire room temperature is low on a thermometer, the receivers of heat feel sufficiently warm. This is the reason why the far-infrared rays save energy.
In general, to generate far-infrared rays alumina is used to make heating plates, because alumina is relatively easy to procure and inexpensive, and also easy to produce a smooth planar surface. However, the problem is that the ceramic substratum must contain a special ceramic capable of generating far-infrared rays of a required wavelength. To satisfy this requirement, the plates become thick and heavy. The thick and heavy heating plates lead to a thick and heavy panel heater. In addition, the thick plates take time to become heated, thereby increasing the consumption of electricity.
The present invention is directed toward an improved ceramic heating plate, which solves the problems discussed above with respect to the known ceramic far-infrared ray plates. Thus an object of the present invention is to provide a thin and lightweight ceramic heating plate without trading off the efficiency of generating far-infrared rays.
This object is achieved by providing a ceramic heating plate which comprises a planar body including a ceramic substratum covered with a far-infrared ceramic layer on its top surface; a heating sheet attached to the back surface of the substratum, the heating sheet including a pair of lead terminals through which the heating plate is connected to a source of power; and wherein the ceramic layer contains ceramic particles exposed above the surface thereof so that far-infrared rays are radiated outside directly therefrom.
Other objects and advantages of the present invention will become more apparent from the following detailed description, when taken in conjunction with the accompanying drawings which show, for the purpose of illustration only, one embodiment in accordance with the present invention .